Bird seen in September, October (3)
I believe the answer is:
roc
'bird' is the definition.
(mythological bird of prey)
'in september october' is the wordplay.
'in' says the answer is hidden in the clue.
'ROC' can be found hidden inside 'september october'.
'seen' acts as a link.
(Other definitions for roc that I've seen before include "Big bird" , "Large bird of legend" , "Mythical monstrous bird" , "Vast legendary bird" , "Vast bird of legend" .)